Battery diagnostic system

Abstract

A battery diagnostic system includes an interpolation processing unit, a degradation estimation unit, a degradation prediction unit, and an output unit. When a part of the battery load history is missing, the interpolation processing unit interpolates the missing part using the rest of the constituent data. The degradation estimation unit estimates, based on the battery load history, a present degradation state of the secondary battery and a cause of degradation that has brought about the degradation state. The degradation prediction unit predicts, using a predicted battery load, the present degradation state and the cause of degradation of the secondary battery, a predicted degradation state of the secondary battery that will occur in the future upon having been used in the use mode. The output unit outputs the predicted degradation state of the secondary battery.

What is claimed is: 
     
         1 . A battery diagnostic system comprising:
 a load history acquisition unit configured to acquire a battery load history which is a history of a load applied to a secondary battery;   an interpolation processing unit configured to, when a portion of constituent data of the battery load history is missing, estimate and interpolate the portion of constituent data using the rest of the constituent data;   a degradation estimation unit configured to estimate, based on the battery load history, a present degradation state of the secondary battery and a cause of degradation that has brought about the degradation state;   a degradation prediction unit configured to predict a predicted degradation state of the secondary battery that will occur in a future upon having been used in a future use mode of the secondary battery for diagnosis, using a predicted battery load indicating a load predicted to be applied to the secondary battery according to the future use mode of the secondary battery and the present degradation state and the cause of degradation of the secondary battery estimated by the degradation estimation unit; and   an output unit configured to output the predicted degradation state of the secondary battery predicted by the degradation prediction unit.   
     
     
         2 . The battery diagnostic system according to  claim 1 , further comprising a predicted load generation unit configured to, when the secondary battery is used according to the future use mode of the secondary battery, identify a load predicted to be applied to the secondary battery and generate the predicted battery load. 
     
     
         3 . The battery diagnostic system according to  claim 2 , wherein the predicted load generation unit generates the predicted battery load when the secondary battery is used in the use mode corresponding to the battery load history according to a learning result using the battery load history. 
     
     
         4 . The battery diagnostic system according to  claim 1 , further comprising a remaining value evaluation unit configured to evaluate a remaining value of the secondary battery when used in the future use mode, by using the predicted degradation state of the secondary battery predicted by the degradation prediction unit. 
     
     
         5 . The battery diagnostic system according to  claim 4 , further comprising a rank identifying unit configured to rank the secondary battery with respect to the predicted degradation state of the secondary battery using a state of a battery component of the secondary battery predicted by the degradation prediction unit, wherein
 the remaining value evaluation unit evaluates a remaining value of the secondary battery using a rank of the secondary battery determined by the rank identifying unit.   
     
     
         6 . The battery diagnostic system according to  claim 5 , wherein the rank identifying unit ranks the secondary battery with respect to the predicted degradation state of the secondary battery using the cause of degradation of the secondary battery predicted by the degradation prediction unit in addition to the state of the battery component of the secondary battery. 
     
     
         7 . The battery diagnostic system according to  claim 4 , wherein the remaining value evaluation unit calculates the remaining value of the secondary battery as an amount of money using a reference value determined for a battery component of the secondary battery and a state of the battery component of the secondary battery predicted by the degradation prediction unit. 
     
     
         8 . The battery diagnostic system according to  claim 4 , further comprising a proposal unit configured to propose a future handling mode of the secondary battery to increase the remaining value of the secondary battery using the remaining value of the secondary battery evaluated by the remaining value evaluation unit and a handling criteria related to future handling of the secondary battery. 
     
     
         9 . The battery diagnostic system according to  claim 8 , further comprising a condition input unit to which the handling criteria related to future handling of the secondary battery is input, wherein
 the proposal unit proposes a future handling mode of the secondary battery to increase the remaining value of the secondary battery using the handling criteria input to the condition input unit.   
     
     
         10 . The battery diagnostic system according to  claim 1 , wherein
 the degradation prediction unit estimates   a calendar degradation amount caused by calendar aging that progresses with lapse of time regardless of energization to the secondary battery and further progresses by increasing a temperature of the secondary battery, and   a cycle degradation amount caused by cycle aging that progresses by energization of the secondary battery and further progresses by energization in a state where a temperature of the secondary battery is low, and   the degradation prediction unit estimates the cause of the present degradation state of the secondary battery using the calendar degradation amount and the cycle degradation amount in the present degradation state of the secondary battery.   
     
     
         11 . The battery diagnostic system according to  claim 1 , wherein
 the interpolation processing unit calculates a temperature of the secondary battery as the portion of constituent data using following formula (1) and formula (2):
     T   n   =T   n−1   +ΔT   n   (1)
 
   
       
         
           
             
               
                 
                   
                     
                       Δ 
                       ⁢ 
                       
                         T 
                         n 
                       
                     
                     = 
                     
                       
                         
                           ( 
                           
                             
                               T 
                               
                                 n 
                                 - 
                                 1 
                               
                             
                             - 
                             
                               Tam 
                               
                                 n 
                                 - 
                                 1 
                               
                             
                           
                           ) 
                         
                         R 
                       
                       × 
                       
                         
                           Δ 
                           ⁢ 
                           t 
                         
                         C 
                       
                     
                   
                 
                 
                   
                     ( 
                     2 
                     ) 
                   
                 
               
             
           
         
         in which T n  (n=1 to N) represents the temperature of the secondary battery, Tame (n=1 to N) represents an outside temperature around the secondary battery, R represents an outside air heat dissipation resistance of the secondary battery, Δt represents a sampling cycle, and C represents a heat capacity of the secondary battery.